Venetian blind assemblies have been proposed for use in window units where the blind assembly is positioned behind glazing any number of different ways. For example, the blind assembly may be adjacent a single pane of glass, may be positioned between two panes, or even positioned in a triple pane window unit. In those units having two or more panes, blind assemblies may in addition be sealed with respect to the panes such that the unit forms a hermetically sealed window unit to provide superior insulation properties. In all forms of units, including single and multiple pane constructions and unsealed and hermetically sealed constructions, it is desirable to have a single effective tilting control mechanism by which the tilt of individual slats of the blind assembly may be easily and accurately regulated using a minimum of force and where the degree of force necessary to tilt the slats remains substantially uniform during the complete range of tilting.
It is also desirable in venetian blind assemblies in order to facilitate placement in a window unit that the blind assembly be fully reversible in a window opening, that is to say, that the top and bottom ends of the blind be reversible in the unit or that the top and bottom ends of the unit be reversible. This reversible feature in turn requires a tilting transfer mechanism which may work equally as well in one position of the blind assembly or window unit as in a reverse position.
Further it is desirable in window units having two or more spaced panes that the slats of the blind assembly in the open position occupy as much of the space between the panes as possible in order to reduce expense of blind assembly and to reduce operating forces. If smaller width slats are utilized where the width of the slat is substantially less than the space between panes, more slats will be required to completely close the window opening thus increasing expense of manufacture and assembly as well as forces necessary to operate the tilting mechanism.
A problem with many hermetically sealed units in particular has been the difficulty of providing controls exterior of the window unit by which the tilting of slats of the blind assembly within the unit may be regulated while at the same time preserving the integrity of the sealed unit. Controls extending through the framing forming the unit wear after use increasing the difficulty of maintaining the sealing of the unit.
Magnetic couplings have been proposed for hermetically sealed window units to connect an operating member exterior of the unit to a blind operating element on the interior of the unit. See for example U.S. Pat. Nos. 3,022,549 dated Feb. 27, 1962 and 3,129,471 dated Apr. 21, 1964. A problem with such magnetic couplings to date has been to design one which is small in size and which will at the same time have sufficient coupling strength to enable the slats of the blind to be tilted throughout their complete operating range.
It is therefore an object of my invention to provide for a venetian blind tilting transfer mechanism in which the force necessary to operate the mechanism remains substantially constant throughout the complete range of operation and which is adaptable for use with venetian blind assemblies having large width slats as well as narrow width slats.
It is a further object of my invention to provide a tilting transfer mechanism which is applicable for use with a blind assembly that may be reversed in a window unit or where the unit may be reversed in a window opening or even where the blind or unit may be installed at an angle to the vertical axis.
A further object of the invention is to provide for a tilting transfer mechanism having a minimum of parts and which utilizes conventional blind assembly structure, as for example, a tape cable for transferring tilting forces to the slats of the blind assembly.
It is a further object of my invention to provide for a magnetic coupling connecting exterior controls with interior operating elements of a tilting transfer mechanism of a venetian blind assembly positioned in a hermetically sealed window unit where the coupling is small in size and does not interfere with the movement of the slats.